# 计算器可以实现(加减乘除四则运算)被除数不能为零
first = float(input("请输入第一个操作数"))
second = float(input("请输入另一个操作数"))
opt = input("请输入操作运算")
if opt == "+":
    print(first, opt, second, "=", first + second)
elif opt == "-":
    print(first, opt, second, "=", first - second)
elif opt == "*":
    print("%lf*%lf=%lf" % (first, second, first * second))
elif opt == "/":
    if second == 0:
        print("被除数不能为零")
    else:
        print(first, opt, second, "=", first / second)
